Variable condenser with small loss



Nov. 16 ,1926.

E. @CM1-@ VARMBLE CONDENSER WITH SMALL LOSS Filsd June 19, 3.925

Patented Nov. 16, 1926. i l

UNITED STATES y 1,606,958 PATENT oFFICE.

EDMOND PICARD, or Panis, FRANCE.

VARIABLE coNDENsERfwITHsMALL Loss.

'Appiictinn mea June 19, 1925, serial Noeaasfi, fand 'in France AJune s,1925.

The present-invention relates to a variable condenserladapted for usewith high frequency circuits, and which is specially constructed with aView to obtaining-a high 1n- I sulationv and'to reducing to a minimumthe residual capacity, the loss by dielectric hysteresis, and otherprejudicial effects.

A Inthe fsaid variable condenser, the movable element orrotorpismaintained between 1 two metallic cheeks or end plates Vwhich are inparallel disposition and are connected together by suitablepostsoruprights. The stationary element or stator lis supported by'two'c'ross-piecesfmade of insulating material, which l"are secured `to thesaid uprights by 'suitable 2 connecting members..

VI preferito construct the saidcross-pieces in the "form of r'odsmadeof-meltedquartz or silica, and suitable straps may be attachedto"theirendsfor connecting them to the frame of the instrument.

To provide for l the Vsuitable mounting of the said condenser elementswith reference to one another, and for the proper assembling of thevarious parts of the instrument without the occurrence of prejudicialinternal effects, certain of the holes for the screws attaching theseveral parts are elongated, thereby ofering a certain latitude for mthe adjustment.

The appended drawing shows Dy way o f example a perspective yiew of 011eembodiment of my said invention.

The rotor and stator elements or members of the said variable condenserconsist,- 1n the known manner, of metallic plates which are superposedwith a uniform spac1ng. The rotor 1 is mounted on the shaft 2 which 1ssupported by two parallel metallic plates 3 and 4: which are connectedtogether by the posts 5.

The plates forming the stator 6 are connected at each side, by solderingor like means, with a metallic block 7 which is supported through themedium of a connecting member or strap 8 by an insulating crosspiece 9secured to the two adjacent posts by connecting straps 10 analogous tothe member 8.

The two cross-rods 9 supporting the stator 6 consists preferably ofmelted quartz or silica, this being an insulating material whichpossesses the maximum qualities with reference to high frequencycurrents.

In addition to a very considerable resistivity, quartz possesses theknown property of reducing to a minimum the residual capacity,` the lossby -dielectric hysteresis and other prejudicial effects.

`Atieach'end'of the cross-rods 9, Ipreferablyfsecure a connecting strap'or member 11for attaching the instrument to a suitable support.Eachmemb'er 11 consists of two parts which are screwed together andwhich for'matoneend an apertured angle piece 12 andat-'the other'a-collar 13 which Y fits upon the'crosslfpi'ec'e 9. The hei` ht of themembers 11 is such that thep ane of the four an'gl'ei' pieces 12issituated above the upper plate 3,s`o that'when the instrument issecuredfto'ap'anel -or other flat 'member by means of the saidcrosspieces 59, none ofthe metallici partsconnected with the stator willbeinconta'ct "with the "said l fiat member.

Tli'ei'condenser according to the'invention is `thus mount'e'dafter the'manner of the knownl'condense'rs,1. e. the shaft@ of the rotor'traverses, without Contact, the panel to which the instrument issecured; on the outer end of the said shaft is disposed a onltrol knob18 provided with a graduated The terminals for the current may berespectively disposed on one 'of the blocks 7, lfor the stator, and onthe shaft 2 by means of a soldered flexible wire, for the rotor.

To facilitate the assembling of the parts and the adjustment of therelative positions of the two main elements 1 and 6, the connectingmembers or straps 8 andv 1() are secured respectively to the block 7and'to the posts 5 by screws 111 passing through slots 15 in saidconnecting members.

Certain of the posts 5 are secured to the end plates 3 and l by screws1G passing through slots 17 in the said plates.

In this manner I mount the Said instrument by first screwing tightly allthe screws which have no play in their apertures, and then by screwingall the screws passing through slots, so that there will be set up nointernal stresses which would be prejudicial to the substantialconstruction "of the instrument.

I regulate the stationary element 6 relatively to the movable element 1,by displacing the latter by sliding it upon the crosspieces 9 and bymoving cach block 7 relatively to the connecting member 8; this motionmay take place by reason of the slots 15 in the Said connecting membenObviously', the condenser of the simple type which has been hereinbeforeset forth is given solely by Way of example, and it is susceptible ofall desired improvements such as are usually made in this class ofinstrument, i. e. slou7 movement of the rotor, devices for taking up theplay, and the like, without departing from the principleof theinvent-ion.

l claim as my invention: f

l. A variable condenser, comprising va :tranne consisting of a pair otspaced cheek plates, and a plurality of posts connecting the sa1ne;apair of cross-rods carried by said posts and constructed of siliciousinsulating material; a metal block carried by each rod; a set of statorplates carried jointly by said blocks; a set of rotor plates forcooperation with the statorplates;.a Shaft to which the rotor plates areattached journaled in said cheek plates; an operating member attached tosaid shaft; and fastening straps secured to the ends of said rods forattaching the instrument to a supporting panel.

2. A variable condenser, comprising a frame; a pair ofoppositely-located crossrods attached to the frame and constructed ing aset of plates for cooperation with the Stat-or plates; and. fasteningstraps secured to the ends of said vrods for attaching the instrument toa supportingl panel.

8. A variable condenser, comprising a frame consisting of a pair ofspaced cheek plates, and a plurality of posts connecting the same; apair ot oppositely-located crossrods i'nade of silicious insulatingmaterial; a set oi' supporting straps for said rods havingscreW-and-slot connections for adjustably securing them to said posts; ametal block carried by each rod; a set of stator plates carried jointlyby said blocks; a set ot rotor plates for cooperation with the statorplates; a shaft to which the rotor plates are attached journaled in saidcheek plates; an operating member attached to said shaft; and fasteningstraps secured to the ends of said rods for attaching the instrument toa supporting panel. n n

et. A variable condenser, according to claim 2, in which the statorplates are carried by two metal blocks; and in Which a supporting st-rapis provided for each block to fasten the saine to the adjacent rod,jeachstrap having an adjustable screW-and-slot connection With therespectiveblock.

ln testimony whereof I aiX myjsignature.

EDMOND PICARD.

